1. Field of the Invention
The present invention relates to a facsimile apparatus to be used with an external telephone set connected thereto and to a telephone terminal apparatus having telephone (voice) and facsimile (image) communication functions, wherein selection between telephone and facsimile communications is controlled by monitoring particular signals sent through a telephone line.
2. Description of the Prior Art
There have been known facsimile apparatuses to be used with telephone sets connected thereto, including, such as, cordless telephone sets or automatic answering/recording telephone sets.
As is known, the automatic answering/recording telephone set (hereinafter referred to as "AARTS") is used for recording an incoming message from a caller and reproducing the recorded incoming message. The AARTS is generally provided with a remote control function which allows a user, for example, to hear the recorded incoming message from another telephone, such as, a public telephone.
In general, when using the remote control function, the user first makes a call to the AARTS. Thereafter, during the AARTS reproducing and sending a recorded outgoing message, the user inputs a specific ID code assigned to the AARTS using a pushbutton dial of the calling telephone so as to set the AARTS ready for the remote control. The user then inputs a predetermined numeric command (for example, [22]: rewind tape; [23]: reproduce or play back recorded incoming message) using the dial of the calling telephone so as to hear the recorded incoming message or in some cases to monitor a condition of a user's room.
On the other hand, in general, the facsimile apparatus is automatically set to an image signal receiving state when detecting a CNG signal or when detecting no sound signal for several seconds. The CNG signal is a facsimile communication start signal which is transmitted from a caller facsimile apparatus when the caller facsimile apparatus is operated under an automatic calling mode.
Conventionally, when the remote control is performed to the AARTS connected to the facsimile apparatus, the following problem has been encountered:
Specifically, when no sound signal is detected for several seconds, which is likely to occur during the AARTS rewinding the tape, the facsimile apparatus is automatically connected to the telephone line so as to be set to the image signal receiving state. As a result, the remote control of the AARTS becomes practically ineffective.
On the other hand, there has been available the so-called direct inward dialing (DID), wherein a plurality of phone numbers are assigned to one subscriber line corresponding to equipped terminal units, respectively, and when a call is made using one of the assigned phone numbers, a designation signal indicative of the corresponding terminal unit is sent from the telephone exchange. In the direct inward dialing, a particular adapter is used, working as switching means, for switching between the terminal units according to the received designation signal. Accordingly, when one of the terminal units is a telephone set and another thereof is a facsimile apparatus, the adapter switches between the telephone set and the facsimile apparatus according to the received designation signal, i.e. the dialed phone number.
However, in the direct inward dialing with such an adapter, once the telephone line is connected to the facsimile apparatus, the telephone line can not be connected to the telephone set unless another call is made. Accordingly, the image data and the voice message can not be transmitted in series during one call.